[92GTA]

I'm putting together the base tune for my Holley Terminator Stealth on my 461 stroker.

With my carb, I always had hard cranking when hot and I think my craning timing wasn't dialed in. The previous owner setup the MSD RTR and it's curve.

Here are my engine specs:

461ci Butler stroker kit assembled & dyno'd by Houston Engine & Balancing (fully blueprinted/balanced):
1969 Pontiac 400ci XH code engine block, 0.030" over, square decked, bored & honed w/torque plate, ARP bolts. Dayco harmonic balancer. Eagle nodular high carbon crank (polished), Eagle 4340 forged H-beam rods, -28.56cc ROSS forged pistons (~9.9cr with 670 heads). Pontiac 670 heads 72cc, Ferrea SS valves - 2.110" intake & 1.770" exhaust, hardened seats. 9.200" pushrods, COMP Cams 995 1.437" Dual Springs 340lb/in @1.150", COMP Cams chromoly steel retainers. COMP Cams XE274H hydraulic flat tappet camshaft, 274/286, .488/.491, 110 LSA, COMP Cams lifters, COMP Cams Magnum 1.5 roller tip rockers. Edelbrock Torker II, professionally ported

My crank timing seems to be at 10-12 and my total timing is 32 degrees the way the previous owner setup the distributor.

1) For the Holley, should I start with the 15 degrees crank timing it defaults to? Also, the base timing table from Holley goes up to 44 degrees! Way too high. I'm thinking I should re-scale it for 35 max (only 91 octane in CA, no 93).

2) At what RPM after idle should I start bringing in more timing and by what RPM should I be all in? I'm guessing right off idle start increasing, then all in by 3,000?

3) Far as rev limiter, what do you guys think based on my engine? I'm thinking a high of 5,600 with a low of 5,500 then setting my MSD box's limiter to 5,700 as a backup for the ECU limiter.

Aside from all the other really basic Holley EFI base settings, anything else you would recommend based on my 461? The engine has about 20K miles on it now. I street drive the car as often as possible but also will be doing some road racing starting next year.

Any Holley EFI tuning tips and tricks you guys have learned that help make your Pontiac happy, please share.

Thanks!

[JLMounce]

Some of this will be trial and error based on what your engine likes. If you currently start the car at around 10 degrees of timing, I'd target that to begin with. That doesn't mean that's where your idle timing is actually going to end up.

The reason you're seeing a max of 44 degrees for the timing table is because that's about what the sweep will allow of the distributor before the spark starts jumping to a different terminal, or not at all. You need that amount in there to act as your vacuum advance. Your distributor is currently setup with 32 degrees of total. Your vacuum advance would typically be 10-12 degrees on top of that. For a street driven car, you want that extra lead for low load driving. Keeps the engine cool, lowers egt's increases fuel mileage.

I don't have first hand knowledge of the basic setup for the holley stuff, but if it's like the FiTech you likely have something like a 1000 or 1100 rpm breakpoint which is your off-idle timing. To start with use that breakpoint to start bringing in your advance.

With the rods you have in the engine, you can pretty safely allow for a higher rpm limit, even if you're not actually making power up there. If the engine was on a dyno you should have a good idea about where the peak power is and how quickly power falls off after peak. Your shift point should be such that you maximize average power/torque so use that data to help you decide on a shift point, then allow some RPM before you limit it after that.

You'll likely need to tune the accelerator functions for tip-in and you'll likely need to also tune around the decel fuel cut, or turn it off. Every engine will react a bit differently, but you can likely assume that you'll need to lower the map cut point for dfco and you'll likely need to add fuel to your fast accel functions to avoid lean tip-in. Those things seem to be common among these types of systems.

[92GTA]

Thanks for the feedback.

To be clear, my MSD RTR (which is mechanical advance) is coming out and a Holley Dual Sync is going in, along with the 6EFI CD box. So the ECU will be controlling timing 100%, that's why I was looking at the timing table and not just being able to rely on the previous distributors setting. I get what you are saying, also I mis-spoke, the full timing at full load by Holley default is 34, 44 is full timing at the least load.

My commanded idle is 875, so 1,000RPM seems fair to start bringing in the timing. The Holley table is showing it increasing right from 15 during crank, to 25 right after (500RPM & higher) to all in at 3K.

I expected my tip-in to be a future challenge for sure, along with cold start fueling. I didn't even think about changing the decel, all the videos I've seen about that are about making the exhaust pop by turning it off and I DON"T want that ricer sound.

Thanks

[Scott65]

If it was hard to crank before, and you have total control of the timing, use less cranking advance. I think i run 6 or 8 on mine to help ease cranking. Once it fires it runs on the regular timing curve.

[92GTA]

Originally Posted by Scott65

If it was hard to crank before, and you have total control of the timing, use less cranking advance. I think i run 6 or 8 on mine to help ease cranking. Once it fires it runs on the regular timing curve.

Good to know, thanks! I wasn't sure what direction to go to start from.

[Scott65]

Experimentation is easy with a laptop! Just experiment til you find what works best.

[92GTA]

Originally Posted by Scott65

Experimentation is easy with a laptop! Just experiment til you find what works best.

For sure, just looking to get a good solid common sense general base to start from is all.

I've been tuning OEM EFI for 20 years, just never used Holley or of course done an old Pontiac engine.

[Scott65]

I understand. Luckily, a Pontiac doesn't know what brand it is, and tuning is basically the same. Reminds me of years ago when a 'glide "wouldn't work in a Pontiac"...

[darbikrash]

Originally Posted by 92GTA

I'm putting together the base tune for my Holley Terminator Stealth on my 461 stroker.

With my carb, I always had hard cranking when hot and I think my craning timing wasn't dialed in. The previous owner setup the MSD RTR and it's curve.

Here are my engine specs:

461ci Butler stroker kit assembled & dyno'd by Houston Engine & Balancing (fully blueprinted/balanced):
1969 Pontiac 400ci XH code engine block, 0.030" over, square decked, bored & honed w/torque plate, ARP bolts. Dayco harmonic balancer. Eagle nodular high carbon crank (polished), Eagle 4340 forged H-beam rods, -28.56cc ROSS forged pistons (~9.9cr with 670 heads). Pontiac 670 heads 72cc, Ferrea SS valves - 2.110" intake & 1.770" exhaust, hardened seats. 9.200" pushrods, COMP Cams 995 1.437" Dual Springs 340lb/in @1.150", COMP Cams chromoly steel retainers. COMP Cams XE274H hydraulic flat tappet camshaft, 274/286, .488/.491, 110 LSA, COMP Cams lifters, COMP Cams Magnum 1.5 roller tip rockers. Edelbrock Torker II, professionally ported

My crank timing seems to be at 10-12 and my total timing is 32 degrees the way the previous owner setup the distributor.

1) For the Holley, should I start with the 15 degrees crank timing it defaults to? Also, the base timing table from Holley goes up to 44 degrees! Way too high. I'm thinking I should re-scale it for 35 max (only 91 octane in CA, no 93).

2) At what RPM after idle should I start bringing in more timing and by what RPM should I be all in? I'm guessing right off idle start increasing, then all in by 3,000?

3) Far as rev limiter, what do you guys think based on my engine? I'm thinking a high of 5,600 with a low of 5,500 then setting my MSD box's limiter to 5,700 as a backup for the ECU limiter.

Aside from all the other really basic Holley EFI base settings, anything else you would recommend based on my 461? The engine has about 20K miles on it now. I street drive the car as often as possible but also will be doing some road racing starting next year.

Any Holley EFI tuning tips and tricks you guys have learned that help make your Pontiac happy, please share.

Thanks!

I have a 467 stroker w/round port Eheads, 10:75 compression, OFII cam and Holley Terminator controlling a Dual Sync distributor.

Here is my timing map, which should get you started. The engine dynoed @ 550 hp, 600 lb/ft.



That table does not control cranking timing, you set advance at cranking here:

[GTO JONES]

I need to show this to my son and see if it would help mine. Sometimes its hard to start, don't know if its the settings or the operator !

[Scott65]

Originally Posted by GTO JONES

I need to show this to my son and see if it would help mine. Sometimes its hard to start, don't know if its the settings or the operator !

There's other things besides timing that can affect hard starting too. I had to turn off the priming pulse at 180 degrees and above, and decrease cranking pulsewidth a good bit from above 160 degrees. Having all this stuff so adjustable is both a blessing and a curse. But the good news is you can eventually make all situations perfect with patience.

[darbikrash]

Originally Posted by Scott65

There's other things besides timing that can affect hard starting too. I had to turn off the priming pulse at 180 degrees and above, and decrease cranking pulsewidth a good bit from above 160 degrees. Having all this stuff so adjustable is both a blessing and a curse. But the good news is you can eventually make all situations perfect with patience.

^^^^This^^^^

I find its best to turn off the fuel prime altogether, mine starts much easier at all temps without it. Its better to set the cranking fuel where the engine likes it best at all temperatures using a table- every engine is different, this requires some experimentation.

For Holley Terminator, the best place to manage cranking fuel is this table:

[Formulajones]

Originally Posted by Scott65

There's other things besides timing that can affect hard starting too. I had to turn off the priming pulse at 180 degrees and above, and decrease cranking pulsewidth a good bit from above 160 degrees. Having all this stuff so adjustable is both a blessing and a curse. But the good news is you can eventually make all situations perfect with patience.

It's not timing related because none of that has changed. We aren't yet using the timing control functions of the unit. This thing used to start with the blip of the key with a carb on it. So the starting is certainly fuel related.

I've tried several things with little result. I currently have the exact same start fuel parameters that are in my Chevelle with the same EFI unit and the Chevelle starts very nice in all conditions. The GTO either doesn't like it or dad is doing something I'm not aware of.
The problem is that I don't drive the car and run errands, so I can't duplicate the situations he's putting the car in. To me it acts as though it's not getting enough fuel both with either the initial pump shot when you turn the key on and not enough during crank either, and I feel the IAC really isn't quite big enough for a 571ci engine. I think that can all be tuned around if I ever get time to play with it.

[Formulajones]

Originally Posted by darbikrash

^^^^This^^^^

I find its best to turn off the fuel prime altogether, mine starts much easier at all temps without it. Its better to set the cranking fuel where the engine likes it best at all temperatures using a table- every engine is different, this requires some experimentation.

For Holley Terminator, the best place to manage cranking fuel is this table:

When I turn off or greatly reduce the fuel prime shot with key on it's even worse. I had to put that back at 150 which is the base setting that comes in the street strip tune to start with.
And if I turn the cranking fuel down to where you're showing in that graph, it won't even start at all.
I'd have to look at the tune again but I believe both cars are up in the 20's from 140 degrees and up and it works fine on the Chevelle, not so much on the GTO. I'm thinking about turning the initial prime shot with key on up over 150 and see what that does.

[Scott65]

Sometimes it can be helpful to use the throttle to find where you're at. If a little throttle opening helps, its probably a little fat. If flood clear amounts of throttle help its really fat. This is one of the tougher areas to get right, especially at every cold start temperature.

[Scott65]

As far as the IAC, that should be easily fixable with the throttle stop screw. Hot, happy idle with the IAC barely open should make it good under start up/cold conditions.

[Formulajones]

Basically I have the IAC at zero at idle in park, it might flicker 1 or 2%, then it comes up into the teens when in gear idling.

That's about as far as I'm willing to go with it because it starts to lose control of the idle speed if I go much more. That's with a 950-1000 rpm idle too. If I idle it down to say 800 it's even worse. It just acts like it needs a bigger hole.

Where it is now it's fine and drives fine, but I know it could be better, because I had it better with a carb.

I told the guys on the Holley forum I'm about ready to drill holes in the throttle blades and they about had a conniption fit

[Scott65]

If you give the ecu control of the timing, you can use that to help the idle. You can build a "hill" in the timing table that will help stabilize the idle.

[darbikrash]

Originally Posted by Formulajones

Basically I have the IAC at zero at idle in park, it might flicker 1 or 2%, then it comes up into the teens when in gear idling.

That's about as far as I'm willing to go with it because it starts to lose control of the idle speed if I go much more. That's with a 950-1000 rpm idle too. If I idle it down to say 800 it's even worse. It just acts like it needs a bigger hole.

Where it is now it's fine and drives fine, but I know it could be better, because I had it better with a carb.

I told the guys on the Holley forum I'm about ready to drill holes in the throttle blades and they about had a conniption fit

You've probably already done this, but be sure your TPS sensor reads 0% at idle. If it even reads +1% or 2% at (idle) the ECU will enable the acceleration enrichment circuit and you will never get it to idle consistently. I had to replace my TPS sensor as it would not (reliably) return to exactly 0% at idle.

Regarding your IAC sensor, it should read ~ 6%-10% at idle. There is a relationship between the idle (screw) speed adjustment on the linkage and the IAC setting. What you describe suggests the idle screw needs to be adjusted on the linkage first, until the IAC can settle in at ~ 6%-10% at your desired idle speed.

Don't forget to do a TPS reset after any change to the idle screw.

It is hard to imagine the IAC not being large enough for the 571 CID, as you just open up the throttle blades more with the adjustment screw to let enough air in for the IAC to throttle back for a good idle.

That said, you will get better idle performance with full spark control as it is much better to use the ECU commanded spark to keep a smooth idle as already mentioned.

[Formulajones]

Originally Posted by darbikrash

You've probably already done this, but be sure your TPS sensor reads 0% at idle. If it even reads +1% or 2% at (idle) the ECU will enable the acceleration enrichment circuit and you will never get it to idle consistently. I had to replace my TPS sensor as it would not (reliably) return to exactly 0% at idle.

Regarding your IAC sensor, it should read ~ 6%-10% at idle. There is a relationship between the idle (screw) speed adjustment on the linkage and the IAC setting. What you describe suggests the idle screw needs to be adjusted on the linkage first, until the IAC can settle in at ~ 6%-10% at your desired idle speed.

Don't forget to do a TPS reset after any change to the idle screw.

It is hard to imagine the IAC not being large enough for the 571 CID, as you just open up the throttle blades more with the adjustment screw to let enough air in for the IAC to throttle back for a good idle.

That said, you will get better idle performance with full spark control as it is much better to use the ECU commanded spark to keep a smooth idle as already mentioned.

Yep I used to keep the IAC around 10-12% at idle but that requires closing the throttle blades more and the IAC would loose control of idle. The engine doesn't really like it much. What happens then is that putting it in gear the IAC would max at 100% trying to maintain idle. Not good. So it was suggested on the Holley forum to set the IAC in neutral at 0% so that in gear the IAC would have a little more control. Big engine with a big cam it just wants more idle air than that IAC can provide.

TPS automatically does a reset when you cycle the key.

Frustrating deal since my Chevelle with the exact same unit was a breeze to set idle parameters. I feel it's going to take some trickery, tuning and fudging to make it happy.